How can the book industry do what the music industry is in the process of doing, which is creating full-on experiences (live gigs, merchandise, clothes, ...)?

It can't.
The music business is about performances and transient experiences whereas books are more about specific ideas.
With music, even recordings (audio or video) can't capture all the value of a live performance, whereas a book's value is completely encapsulated between the book and the reader. There is no subsidiary value to be monetized.
That is one of the reasons ebooks are so effective; they strip away the material encumbrances without stripping any of the ideas that define the narrative--in techie terms, they are a lossless encoding of the full experience. (Unless you are a smell fetishist. )